如何将枚举值保存到会话中

Question

我正在创建枚举属性.此属性应保存到会话中.我的代码在这里

public enum TPageMode { Edit=1,View=2,Custom=3}

       protected TPageMode Mode { 
            get{
                if (Session["Mode"] == null)
                    return TPageMode.Edit;
                else
                {
                    return Session["Mode"] as TPageMode; // This row is problem
                }                
            }
            set {
                Session["Mode"] = value;
            } 
        }

编译器发布错误 return Session["Mode"] as TPageMode

The as operator must be used with a reference type or nullable type

当我将此行替换为

return Enum.Parse(typeof(TPageMode), Session["Mode"].ToString());

显示此错误

Cannot implicit convert type 'object' to 'TPageMode'

如何从会话中读取枚举值？

Answer 1

试试这个:

return (TPageMode) Session["Mode"];

如错误消息所示,"as"不能与非可空值类型一起使用.如果你然后转换为正确的类型,Enum.Parse 会工作(效率低下):

return (TPageMode) Enum.Parse(Session["Mode"], typeof(TPageMode));